This invention relates to a method of and apparatus for manufacturing sheets having swatches thereon.
The present invention is an improvement over the method and apparatus for the manufacture of sheets having swatches thereon disclosed in U.S. Pat. No. 4,061,521, in which sheets are moved intermittently through a machine to receive rows of swatches thereon. In this patented method, the sheets are conveyed to a register stop at each station where the sheets are registered while swatches are being applied thereto from a rotating swatch-applying cylinder. Although this patented method has been very successful and is a great improvement over the older till box and vacuum transfer system, the patented method still has a number of shortcomings, as will now be discussed.
Various attempts have been made to substantially increase the production speed of this intermittent sheet feed system by trying to control the sheet as it is being conveyed. A slight shifting of the adhesive bearing sheet results in a misregistration of the swatches with preprinted material on the sheet. It is also desired to prevent the sheet from becoming jammed or cocked and not fed properly from one swatch-applying station to the next swatch-applying station; often there are as many as ten or more swatch-bearing stations in a row. The sheets traveling downstream from the first swatch-applying station will have rows of swatches and rows of wet adhesive thereon, all of which make the sheet more difficult to control at higher speeds of travel than are dry sheets without having been converted by the application of one or more rows of swatches applied to the sheet.
The registration of the swatches on the sheets needs to be precise in that the swatches, such as color chips, are often placed adjacent a preprinted description for the color of the adjacent chip. The chip should not overlie or be so close to the printing that the desired appearance for the color sheet or card is disturbed. In some instances, the color chip must be inserted into a preprinted box; and if the chip is out of register only a few thousandths of an inch, the chip may cover one side of the printed box.
When manufacturing color chip sheets, the same machine is often used for various sizes of sheets or chips, for example, from 8 to 23 inches in the longitudinal feed direction of the sheet. The same machines usually are required to apply swatches to paper that is about 0.0035 to 0.004 inch thick, as well as to paperboard that is about 0.008 to 0.010 inch thick. Also, the swatches vary in area, thickness, swatch material, and the pattern of deposition on a sheet.
It is a particular problem from a loss of production and from a time standpoint to change from one job to another job with a change of adhesive and swatch patterns, as well as a change in sheet size in the machines described in the aforementioned patent. The adhesive and swatch-applying cylinders have a fixed circumferential length associated with a particular size of sheet. In some instances where the sheet length is short, the cylinder circumference may be double the sheet length; so that a set of swatches may be applied during each half of a revolution of the swatch-applying cylinder. Of course, many sheets do not have a dimension in the travel direction that is an even number multiple of the cylinder circumference, so that adhesive and swatch-applying cylinders must be replaced with new cylinders having a circumference appropriate for the new sheet length. When there are ten or more cylinders, including adhesive cylinders to be replaced, the job is very time-consuming. Also, the cylinders typically weigh several hundred pounds each and require cranes to lift and transport them. With a change in cylinders, there is also a necessity to change gears and to reset timing cams to properly time the severing of chips from ribbons of chip material and the application of chips in proper register to the printed matter. Also, gear and other changes are needed for the conveying mechanism to stop the pushing of the sheets for proper registration with the cylinders.
The set-up time from running one job for one size of sheet to another job, using another size of sheet and involving the change of cylinders and other attendant changes discussed above, may take another eight hours; and it may take another eight hours or more to finely tune the machine so that it is properly running at high production speed. As the speed of operation is increased during a fine tuning operation, problems arise that were not detected at lower speed operations, and the solution to these problems usually requires a stopping of the machine while adjustments are made. Because the adhesive is wet on the sheets, those sheets in the machine having wet adhesive spots must be removed and scrapped where the adjustment has taken so long that the adhesive becomes dry or substantially dry. This results in sheet spoilage, which becomes very significant if it is taking eight to sixteen hours or more and the running of the machine with sheets during set-up and the fine tuning operations.
Not only is there a significant amount of spoilage during the set-up and fine tuning to a production speed operation of the machine but also during the actual high speed production runs spoilage occurs all too frequently as sheets become jammed. One common source of sheet jamming is the sheet-by-sheet feeder required to place individual sheets from a stock into the swatch placement process. When jamming occurs, the machine is stopped and the jammed sheet and often the sheets that have received adhesive and are downstream of the adhesive station have to be removed from the machine and scrapped. Because the sheets receive wet adhesive and travel at high speeds, sheet jamming occurs with sufficient frequency that both spoilage and lost production time become significant cost factors with this patented system.
From the foregoing, it will be seen that there is a need for a new and improved method of manufacture of swatch-bearing sheets. Preferably, the production speed will be increased several times above the current production speed. Also, the make-ready time and time for fine tuning need to be reduced very substantially from the eight to sixteen hours now used. Further, the sources of sheet jamming need to be reduced and the significantly high scrap rate, e.g., of ten percent or greater, needs to be reduced significantly to one-half or less than current scrap rates.